In modern communication devices, two-dimensional printed circuit board antennae allow an antenna to be implemented by printing an electrically conductive material on a standard printed circuit board (PCB). Such printed circuit board antennae are very cost-effective and minimize the amount of space needed to implement the antenna of the communication device.
FIG. 1 is a schematic diagram depicting a conventional three-dimensional antenna 100 translated to the plane of the printed circuit board 110. The dipole radiator element 120 projects orthogonal to the ground plane 140 of the printed circuit board 110. The ground plane 110 replaces the return dipole 130 in the first projection.
The antenna is reduced to two dimensions by rotating the dipole radiator element 120 down to the plane of the printed circuit board 110, as shown in the FIG. 2, which is a top view of a printed circuit board 210. The dipole radiator element 220 is implemented on the circuit board 210 using an electrically conductive material such as copper. The radiator 220 is disposed adjacent to, but not on or over, the ground plane 230. In the embodiment of FIG. 2, the radiator 220 is a linear element and extends orthogonally from the ground plane 230.
The printed circuit board antenna of FIG. 2 generates a largely omnidirectional radiation pattern, i.e., the strength of the signal is approximately equal in all directions. In some applications it is desirable to generate a focused radiation beam and to be able to have control over the direction and strength of the generated beam.